The river tours are great, an excellent and alternative way to see London, you can get off at places like Tower of London, Greenwich, Kew, Hampton Court etc.

The Jazz Cafe in Camden is my favourite place to see bands, they have "an eclectic mix" of jazz/soul/dance/latin acts. It's tiny and you can get as close to the stage as you want, also got a fairly decent restaurant overlooking the stage.

There's a good cheap(ish) Japanese restaurant chain in London called Wagamama, worth checking out for high qualuty fast food and the excellent Sapporo beer.

If you want cheap and decent Indian food the best places I know are Tayyabs in Fieldgate Street, and Mirch Masala in Commercial Rd (both Whitechapel) neither sell alcohol but you can bring your own (I think)

There's a good Indonesian restaurant called Melati in Brewer St (nr Picadilly Circus)

The best shawarma in London is at Maroush in Edgware Rd

Cafe Mandola in westbourne Grove is an excellent Sudanese restaurant.